1. Field of the Invention
The present invention relates to display devices and electronic apparatuses that provide improved visibility outdoors.
This application is based on Japanese Patent Application No. 2008-226068, the content of which is incorporated herein by reference.
2. Description of Related Art
Display screens of digital cameras and portable phones can exhibit good visibility when used indoors, but when used outdoors, the sunlight can sometimes reflect off the surface of the display screen, lowering the visibility. In particular, when a cover is provided for protecting the display screen, this problem of lower visibility becomes more obvious since reflections off the front and back surfaces of the cover are added to the reflection off the surface of the display screen.
As a common approach for ensuring good visibility of display screens in an outdoor environment, one known method of making the display screen brighter involves increasing the power of a backlight. However, this method is problematic in that the number of pictures that can be taken or the operating time is significantly reduced due to the increase in the amount of power consumed by the backlight. In the related art, a method of reducing power consumption by reducing the size of a display region in the display screen is employed as a known countermeasure against such a problem. For example, see Japanese Unexamined Patent Applications, Publication Nos. 2006-221083 and 2000-357075.
In the related art mentioned above, a plurality of backlight sources are provided, and on/off control is performed on each of the light sources, so as to illuminate a predetermined region of the display screen. For example, an image can be displayed only in the right half of the display screen by only turning on a light source that illuminates the right half of the display screen, thereby reducing the power consumption.
However, in the related art, although the image can be displayed on the display screen by splitting it in the vertical direction or the horizontal direction, the image cannot be displayed with the same aspect ratio as the display screen. The reason for this is that the display device of the related art is designed such that the light sources are arranged in the vertical direction or the horizontal direction along an edge of a light guide. When light is emitted from the light sources and subsequently received by the light guide, the light repeatedly undergoes total internal reflection in the light guide so as to be uniformly output from an exit surface of the light guide. Therefore, in order to display the image with the same aspect ratio as the display screen, the light incident on the light guide needs to be output only to a predetermined region of the display screen.